When your car's Check Engine light comes on, it's usually accompanied by a sinking feeling in the pit of your stomach. The light could mean a costly problem, like a bad catalytic converter, or it could be something minor, like a loose gas cap.
If you experience any bleeding period after this 20 days, it will probably be the real period. This normally comes at about 4 to 6 weeks after the miscarriage.
Only now will your levels drop to zero and a new cycle begin. You cannot expect a normal period any sooner than four weeks from this, and up to seven weeks could still be normal. Your total wait time from original miscarriage to first period can creep up to nine or ten weeks and still be normal.